Oh, I've got something unexpected for you. I got bored listening to people going on and on about the Universe being a simulation, so I built a machine that can check if you're in some (but not all) classes of a simulated Universe. Take that, Plato!

It works using Bell's Theorem and the limitations of Turing machines. The former shows that for some types of measurements, the outcomes are purely probabilistic, and do not contain hidden deterministic variables (seems like a dumb way to design a Universe for simulation!). Then Turing machines are capable of computing anything that can be defined as an algorithm (but only things that can be defined in an algorithm!).

Since the former provides a non-deterministic measurement that the latter cannot model, you make a machine that produces those measurements, and ties them to something on a bigger scale (stock market purchases, social media posts, whatever). Then you keep the measurements, and attempt to determine whether they were actually generated with an algorithm (this is very hard but possible in theory -- sort of like reversing a hash). Meanwhile in the Universe upstairs, for the results to appear random enough so that analysis is nontrivial, it must consume extra computation in whatever device is running the simulation. In short, I'm doing a thing that consumes extra processing power.

So logically, if this Universe is being simulated, and someone is observing the machine closely that is doing the simulating, I can pass messages encoded in CPU activity. Just like in computer security where you can extract encryption keys by looking at a video of your power LED!

So if I'm not actually typing this on my laptop right now -- but really am sleeping/dreaming with some equivalent to an EEG monitor or MRI or whatever in some other Universe -- someone may be able to conclude whether this Universe is being generated by my mind or not. In the former case, they may have their answer, but have not woken me up yet. At that time, regrettably, your continued existence is not guaranteed. Sorry about that, but there was science to do!

If you would like to use the device I have built, you can do that. Because of course it's sitting on my desk, connected to a server via MQTT, and subsequently connected to a Lemmy bot. If you message kong_ming on my instance (with a non-blank message), it will use the device as an entropy source to generate an I Ching reading. You know, to help you answer personal questions with only a vanishingly small likelyhood of causing the Universe to cease existing. Sometimes it is down for maintenance, although I just checked in on it now and it seems OK.

I also have a second such device, at an undisclosed location, that is designed to work with a coffee machine. You know, for those times you want coffee that's simultaneously caffeinated and decaffeinated until you drink it.

Anyway, there you go. I've added a feature to the fediverse, I guess.